Total Synthesis of (±)-Leonuketal

Cleavage of a C–C bond is a diversifying process in the biogenesis of seco -terpenoids that has produced fascinating molecular structures. Leonuketal is an 8,9- seco -labdane terpenoid with a unique tetracyclic structure, owing to a C–C bond cleavage event in its biosynthesis. We report the first total synthesis of leonuketal, featuring an unusual Shapiro-type reaction as part of an enabling auxiliary ring strategy, and a novel Au-catalysed spirocyclization of a b-keto(enol)lactone.